Thermoelectric nanocomposite materials

Patent metadata

Field	Value
Publication number	US-12114569-B2
Application number	US-202218061012-A
Country	US
Kind code	B2
Filing date	Dec 2, 2022
Priority date	Dec 3, 2021
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

Abstract

Thermoelectric (TE) nanocomposite material that includes at least one component consisting of nanocrystals. A TE nanocomposite material in accordance with the present invention can include, but is not limited to, multiple nanocrystalline structures, nanocrystal networks or partial networks, or multi-component materials, with some components forming connected interpenetrating networks including nanocrystalline networks. The TE nanocomposite material can be in the form of a bulk solid having semiconductor nanocrystallites that form an electrically conductive network within the material. In other embodiments, the TE nanocomposite material can be a nanocomposite thermoelectric material having one network of p-type or n-type semiconductor domains and a low thermal conductivity semiconductor or dielectric network or domains separating the p-type or n-type domains that provides efficient phonon scattering to reduce thermal conductivity while maintaining the electrical properties of the p-type or n-type semiconductor.

First claim

What is claimed is:

1. A method for forming a thermoelectric (TE) nanocomposite material, the method including steps of:
making or selecting a powder comprising particles of a first semiconductor material X 1 having an n- or p-type conductivity;
making a porous green compact consisting of an interconnected particle network from the powder of the first material X 1 , the compact having an open porosity allowing permeation of the compact with gas or liquid;
infilling and conformally coating all available surfaces inside the porous compact of the first material X 1 with at least one second material having a thermal conductivity lower than a thermal conductivity of the first material to form a composite material of the first and second materials, the second material Y 1 being a semiconductor or a dielectric/insulator material; and
sintering the formed nanocomposite material to remove residual porosity from the composite material and form a nanocomposite solid material with intimately connected p- or n-type networks and having strong chemical bonds at all interfaces;
wherein the nanocomposite solid material retains the nanostructure of the starting nanoparticles within the solid; wherein the nanocomposite solid material maintains a percolating p- or n-type semiconductor network of first material X 1 within the solid second material; and
wherein the second material provides efficient phonon scattering so as to reduce a thermal conductivity of the nanocomposite material while maintaining electrical transport properties of the first material network.

2. The method according to claim 1 , wherein the powder is a nanopowder comprising nanoparticles having a particle size of about 1 nm to about 800 nm.

3. The method according to claim 1 , wherein the porous green compact is formed by pressing the nanopowder of the first material X 1 .

4. The method according to claim 1 , wherein the porous green compact is formed by pre-sintering of the first material X 1 .

5. The method according to claim 1 , wherein the step of infilling and conformally coating all available surfaces inside the porous compact of the first material X 1 with the second material Y 1 is interrupted while the compact retains an open porosity and the step of infilling is repeated with an additional material Y 2 .

6. The method according to claim 1 , wherein the conformal coating comprises nanoparticles or islands of one or more Y 2 , . . . , Y N materials.

7. The method according to claim 1 , wherein all processing steps are conducted in a controlled atmosphere with air-free transfer between steps to provide clean interfaces within the thermoelectric nanocomposite.

8. The method according to claim 1 , wherein the first material X 1 comprises nanoparticles of SnSe, Bi 2 Te 3 , a Bi—Te alloy, a BiSbTe alloy, Bi 2 T 3 /CdTe core/shell nanoparticles, a Zn—Sb alloy, Si, Ge, SiGe, Mg 2 Si, SrTiO 3 , NaCo 2 O 4 , Zn 4 Sb 3 , a Co—Sb alloy, or ZnO.

9. The method according to claim 1 , wherein the second material Y 1 comprises SiC, Al 2 O 3 , ZrO 2 , HfO 2 , SiO 2 , Gd 2 Zr 2 O 7 , and (Zr,Hf) 3 Y 3 O 12 , Si 3 N 4 , AlN, ScN, MgF, CaF, ZnF, AlP, SiS 2 , LiCl, NaCl, MgCl 2 , or CaCl 2 ).

10. The method according to claim 1 , wherein the first material X 1 comprises nanoparticles having at least one length dimension of less than 3 nm.

11. The method according to claim 1 , wherein the process of infilling and conformally coating all available surfaces inside the porous compact of the first material X 1 includes N steps of infilling and coating all available surfaces inside the porous compact of material X 1 with one or more additional materials Y 2 , . . . , Y N while the compact retains an open porosity, where each of the materials Y 1 , Y 2 , . . . , Y N is different.

12. The method according to claim 11 , wherein the N steps of infilling and conformally coating all available surfaces inside the porous compact of material X 1 with materials Y 1 , Y 2 , . . . , Y N are realized by means of atomic layer deposition.

Assignees

• Us Gov Sec Navy

Inventors

• Feigelson Boris N
• Anderson Kevin P
• Greenberg Benjamin L
• Wollmershauser James A
• Jacobs Alan G

Classifications

• H10N10/855

  comprising compounds containing boron, carbon, oxygen or nitrogen · CPC title

• C04B2235/9607

  Thermal properties, e.g. thermal expansion coefficient · CPC title

• C04B2235/5445

  submicron sized, i.e. from 0,1 to 1 micron · CPC title

• H10N10/857

  comprising compositions changing continuously or discontinuously inside the material · CPC title

• C04B35/117

  Composites · CPC title